Phase-Slip Flux Qubits TU Delft In a recent paper submitted to the New Journal of Physics special issue on solid-state quantum information processing, Mooij and Harmans introduce phase-slip flux qubits, which harness quantum tunnelling to realize a superconducting qubit without the use of Josephson junctions. Phase-slip qubits potentially hold two distinct advantages over traditional flux qubits: lower sensitivity to charge noise-based sources of decoherence, and well-defined separation of energy levels of more than 500 GHz, allowing for extremely rapid excitation of the qubit.

Energy Level Separation Energy levels as a function of applied flux for different fluxoid numbers. A phase-slip event changes the fluxoid number n. The arrow indicates the operating point at f= ½.

20050808

Delft Scientists Split Electron Pairs in Superconductors TU Delft "Scientists at Stichting FOM and Kavli Institute of Nanoscience Delft have demonstrated that electrons that normally travel through superconductors in pairs can be seperated while retaining their quantum mechanical kinship. The formation of electron pairs - so-called Cooper pairs - is such a fundamental property of current flow in superconductors that the Delft experiment is considered a breakthrough. It lays the foundation for the realization of a superconducting entangler capable of injecting pairs of entangled electrons into nanoelectronic circuits, an important building block of the quantum computer scientists have been dreaming of for years."

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Robust Entanglement Innsbruck "It is common belief among physicists that entangled states of quantum systems lose their coherence rather quickly. The reason is that any interaction with the environment which distinguishes between the entangled sub-systems collapses the quantum state. Here we investigate entangled states of two trapped Ca+ ions and observe robust entanglement lasting for more than 20 seconds."